1. Field of the Invention
The present invention relates to resin laminates, resin laminates having metal layers and a process for production thereof.
2. Description of the Related Arts
Resin laminates have conventionally been used as films or sheets for wrapping or ornaments, or materials for electric or electronic parts, and resin laminates having metal layers have been used for magnetic tapes, electrostatic capacitors, hot stamping foils, flexible printed circuit board, food wrapping materials or ornaments.
Among these resin laminates, those having styrene-based polymer layer as one of the constituting layers are known. Since the styrene-based polymers used there, however, have atactic configuration, they are unsatisfactory in heat resistance, solvent resistance, hot-water resistance or stiffness.
In the laminates having metal layers, most of the functional films are made of polyethylene telephthalate, polyphenylene sulfide, polyimide, polyamide or polyolefin, but few of them are satisfactorily well-balanced in heat resistance, dimentional stability, chemical resistance, electrical properties, mechanical properties, gas barrier properties and cost.
For example, the polyethylene telephthalate used for electrostatic capacitor has large dielectric loss tangent (tan .delta.) around the glass transition temperature, and poor in frequency properties. In contrast, polystyrenes having atactic configuration excellent in frequency properties are poor in heat resistance.
Films for wrapping food, on the other hand, may be used at high temperatures and at high humidities in some cases. Accordingly, films made of polyethylene telephthalate or polyamide has the possibility of being hydrolyzed, while polypropylene and the like which do not hydrolyze easily are poor in heat resistance. With regard to the film as simple substance, polyphenylene sulfide (PPS) well-balanced in physical properties is small in adhesivity to metals, poor transparency and expensive.
The present inventors have earnestly repeated the researches so as to overcome the said disadvantages of the conventional resin laminates and laminates having metal layers, and to develop a resin laminate and a laminate having metal layer which are excellent in various physical properties.
The present inventors' group has found that a resin laminate having excellent physical properties can be produced by employing as the starting material the styrene-based polymer having high syndiotacticity developed before (Japanese Patent Application Laid-open No. 104818/1987), on which other thermoplastic resins or metals are laminated. Furthermore, they have found that said resin laminate can be produced efficiently by a specified process for producing. The present invention has been completed based on the above knowledge.